Backups
Restoring the last full and then overlaying incrementals is old school and likely to result in a clusterfuck at the end of the day - files which were deleted end up reappearing and directory trees which were moved around show up in both locations.
To get around this you need a database containing a complete file list at any given point in time. Luckliy at least one backup package (Bacula) does this and can use Full+Diff+incrementals to restore an exact image at any given backup WITHOUT needing to shag around with intermediate steps.
As for full backups taking too long: If they do, then use synthetic full backups (Existing F+D+I backups are used to create a new full backup.). Once you have a database containing a full list of files at any given point in time this is trivial. (Bacula can do this too)
Having lost 40Tb disk arrays due to simultaneous drive failures I appreciate the speed in restoration.
If things are really THAT business critical then it's entirely not silly to build a RAID array of RAID arrays (RAID 51 or 61 or 55 or 66), or use cross-site replication and put up with the wastage - but that's not an excuse to get lax about backups.